ClangIndexingSettingsManager doesn't compile in MSVC

ClangIndexingSettingsManager class uses an std::map with std::unique_ptr. MSVC tries to generate a default copy constructor and a default operator=. It fails, because std::unique_ptr cannot be explicitly copied. The compiler issues error C2280 "attempting to reference a deleted function".

To make MSVC cool, one can explicitly delete copy constructor and operator = from ClangIndexingSettingsManager. Suggested fix is to add these two lines to ClangIndexingSettingsManager class:

    ClangIndexingSettingsManager(const ClangIndexingSettingsManager &) = delete;
    ClangIndexingSettingsManager &operator=(const ClangIndexingSettingsManager &) = delete;